North Madagascar Research Articles

Intra-species variability in migratory movement of hawksbill turtles in the southwest Indian Ocean

Implementing effective conservation measures to manage migratory populations is challenging, especially in a relatively inaccessible dynamic environment such as the ocean. With limited financial and human resources, efforts must be intelligently prioritized to achieve conservation success and reduce uncertainties of conservation efforts. The southwest Indian Ocean (SWIO) hosts some of the world’s most important breeding grounds for the Critically Endangered hawksbill turtle Eretmochelys imbricata. However, knowledge gaps remain about the movement patterns of this species. Between 2007 and 2022, we deployed 17 satellite tags onto hawksbill turtles from scattered locations in the SWIO: 16 nesting females—Granitic Islands, Seychelles (n = 9); north Madagascar (n = 5); Moheli, Comoros (n = 1); Juan de Nova, Terres australes et antarctiques françaises (n = 1)—and 1 female bycaught in fisheries (east Madagascar). We found strong variability in migratory movements amongst individuals, particularly in terms of distance and movement persistence. Detailed analysis of movement persistence reveals that these individuals behave differently in neritic and oceanic habitats, with a lower movement persistence in neritic habitats. We identified a total of 12 foraging areas scattered throughout the SWIO, both in coastal and open-sea neritic habitats. These results reinforce the need to consider the importance of neritic habitats, for both migration and foraging, in conservation policies. The quantification of the degree of migratory variability is particularly important to developing conservation plans and strategies at both the national and international level, including the delineation of regional management units (RMUs) in the Indian Ocean.

Limits and CO2equilibration of near-coast alkalinity enhancement

Abstract. Ocean alkalinity enhancement (OAE) has recently gained attention as a potential method for carbon dioxide removal (CDR) at gigatonne (Gt) scale, with near-coast OAE operations being economically favorable due to proximity to mineral and energy sources. In this paper we study critical questions which determine the scale and viability of OAE. Which coastal locations are able to sustain a large flux of alkalinity at minimal pH and ΩArag (aragonite saturation) changes? What is the interference distance between adjacent OAE projects? How much CO2 is absorbed per unit of alkalinity added? How quickly does the induced CO2 deficiency equilibrate with the atmosphere? Choosing relatively conservative constraints on ΔpH or ΔOmega, we examine the limits of OAE using the ECCO LLC270 (0.3∘) global circulation model. We find that the sustainable OAE rate varies over 1–2 orders of magnitude between different coasts and exhibits complex patterns and non-local dependencies which vary from region to region. In general, OAE in areas of strong coastal currents enables the largest fluxes and depending on the direction of these currents, neighboring OAE sites can exhibit dependencies as far as 400 km or more. At these steady state fluxes most regional stretches of coastline are able to accommodate on the order of 10s to 100s of megatonnes of negative emissions within 300 km of the coast. We conclude that near-coastal OAE has the potential to scale globally to several Gt CO2 yr−1 of drawdown with conservative pH constraints, if the effort is spread over the majority of available coastlines. Depending on the location, we find a diverse set of equilibration kinetics, determined by the interplay of gas exchange and surface residence time. Most locations reach an uptake efficiency plateau of 0.6–0.8 mol CO2 per mol of alkalinity after 3–4 years, after which there is only slow additional CO2 uptake. Regions of significant downwelling (e.g., around Iceland) should be avoided by OAE deployments, as in such locations up to half of the CDR potential of OAE can be lost to bottom waters. The most ideal locations, reaching a molar uptake ratio of around 0.8, include North Madagascar, California, Brazil, Peru and locations close to the Southern Ocean such as Tasmania, Kerguelen and Patagonia, where the gas exchange appears to occur faster than the surface residence time. However, some locations (e.g., Hawaii) take significantly longer to equilibrate (up to 8–10 years) but can still eventually achieve high uptake ratios.

The importance of future generations and conflict management in conservation

AbstractThe need to scale‐up conservation initiatives is widely accepted, but understanding how to catalyze the adoption of conservation initiatives remains elusive. To address this challenge, we used diffusion of innovation theory and Best‐Worst Scaling experiments to rank the factors that influence the adoption of Locally Managed Marine Areas (LMMAs) by villages in north Madagascar. The most important driver for respondents to adopt LMMAs was the wellbeing of future generations, while the most important barrier was conflict within and between villages that could arise from the adoption of LMMAs. This emphasis on the benefits and costs of adoption is consistent with diffusion of innovation theory. However, our results indicate that people's intrinsic values (e.g., benevolence and peace) were more important to survey respondents in the adoption of LMMAs than is generally reported in the diffusion of innovation literature. Concerns about conflict from LMMAs and the distribution of livestock incentives warrant further consideration to support the adoption of this conservation initiative in the context of the Sustainable Development Goals. Our study can guide future conservation research and practice to identify the “best” and “worst” attributes of LMMAs and other initiatives to increase the adoption of conservation.

Assessment of Petrophysical Rock Properties in North Madagascar: Implications for Geothermal Resource Exploration

Assessment of Petrophysical Rock Properties in North Madagascar: Implications for Geothermal Resource Exploration

Diagnosis of wet and dry events and its associated atmospheric circulation anomaly over Malawi, Southeast Africa

This paper presents an analysis of December to February (DJF) season wet and dry events and their associated circulation anomalies during the period of 1978–2010 over Malawi. The study was conducted using meteorological daily observed rainfall datasets during the entire study period. A set of regional wet and dry indices with a scheme of classifying their severity was employed to classify the wet and dry into seven different grades using the Z-Index. The results reveal severe wet during 1997 and 2007 rainfall season, while extreme dry events were observed in 1992 and 2000 season. The wind components (u;v) and velocity potential/divergence analysis revealed that dry years were characterized by divergence at low level and convergence at upper troposphere, especially over region of study, Mozambique, Madagascar as well as North Madagascar. It was observed that there is a pattern of enhancement for vertical velocity (Omega) and Relative humidity during wet years and reduction during dry years. The SST uncovers dry years were manifested with negative anomalies over equatorial western Indian ocean and the eastern equatorial Pacific Ocean. Wet years were characterized by a pool of positive anomaly over the south west and equatorial of Indian Ocean, and a negative anomaly in the equatorial Pacific Ocean.

\u2018Barcode fishing\u2019 for archival DNA from historical type material overcomes taxonomic hurdles, enabling the description of a new frog species

Taxonomic progress is often hindered by intrinsic factors, such as morphologically cryptic species that require a broad suite of methods to distinguish, and extrinsic factors, such as uncertainties in the allocation of scientific names to species. These uncertainties can be due to a wide variety of factors, including old and poorly preserved type specimens (which contain only heavily degraded DNA or have lost important diagnostic characters), inappropriately chosen type specimens (e.g. juveniles without diagnostic characters) or poorly documented type specimens (with unprecise, incorrect, or missing locality data). Thanks to modern sequencing technologies it is now possible to overcome many such extrinsic factors by sequencing DNA from name-bearing type specimens of uncertain assignment and assigning these to known genetic lineages. Here, we apply this approach to frogs of the Mantidactylus ambreensis complex, which was recently shown to consist of two genetic lineages supported by concordant differentiation in mitochondrial and nuclear genes. These lineages co-occur on the Montagne dʼAmbre Massif in northern Madagascar but appear to have diverged in allopatry. We use a recently published bait set based on three mitochondrial markers from all known Malagasy frog lineages to capture DNA sequences from the 127-year-old holotype of Mantidactylus ambreensis Mocquard, 1895. With the obtained sequences we are able to assign the name M. ambreensis to the lowland lineage, which is rather widespread in the rainforests of northern Madagascar, leaving the microendemic high-elevation lineage on Montagne d’Ambre in north Madagascar in need of description. We describe this species as Mantidactylus ambony sp. nov., differing from M. ambreensis in call parameters and a smaller body size. Thus, using target enrichment to obtain DNA sequence data from this old specimen, we were able to resolve the extrinsic (nomenclatural) hindrances to taxonomic resolution of this complex. We discuss the broad-scale versatility of this ‘barcode fishing’ approach, which can draw on the enormous success of global DNA barcoding initiatives to quickly and efficiently assign type specimens to lineages.

Contribution to the knowledge of oribatid mites of the genus Austrocarabodes (Acari, Oribatida, Carabodidae) of Madagascar

This work includes taxonomic and faunistic data on carabodid mites (Oribatida, Carabodidae) collected from the Montagne d'Ambre National Park, North Madagascar. A new species of the genus Austrocarabodes is described; A. madagascarensis n. sp. differs from A. similis and A. spathulatus by the presence of foveolae on the body surface. Supplementary descriptions of Austrocarabodes parapustulatus Mahunka, 2009 and A. planisetus Mahunka and Mahunka-Papp, 2011 which were originally described from Madagascar, are presented. The species Austrocarabodes spathulatus Mahunka, 1978 is recorded in Madagascar for the first time.

Source of Unusual Monochromatic Wave Packets Recorded Globally in the Seismograms of 11 November 2018

On 11 November 2018, all global seismic stations recorded unusual long-period wave packets without any discernible body waves. Our analyses show that the wave packets are monochromatic with period 15.6 sec and are fundamental-mode non-dispersive Rayleigh waves. Using the arrival times of wave packets, the source is approximately located at the northeastern edge of the recent earthquake swarm zone, off the east coast of Mayotte, a volcanic island between North Madagascar and East Africa. Synthetic seismograms for an isotropic source at 15 km depth with a transient oscillation of the same periodas that observed in the wave packets, are consistent with the recorded seismograms. We estimate an equivalent magnitude (M w ) of ~4.8 for this source and suggest that a volcanic fluid sphere of radius ~5 km might have generated such radial oscillations. Interestingly, similar monochromatic waves with lesser amplitude were also recorded on many occasions from the same source during 21 June 2018 to 10 September 2019. The period of waves increased from 15.2 sec in June to 15.6 sec in October– November 2018 and then decreased to 15.0 sec in September 2019, which implies an increase and then decrease in radius of the fluid sphere at the source.

Contribution to the knowledge of the oribatid mite genus Angulogalumna (Acari: Oribatida: Galumnidae)

ABSTRACTA new species of the genus Angulogalumna (Oribatida, Galumnidae) is described from leaf litter in evergreen rain forest in the Montagne d’Ambre National Park of North Madagascar. Angulogalumna grishinae sp. nov. differs from Angulogalumna asiatica and Angulogalumna areolata by the presence of setiform bothridial seta, localization of lamellar seta medial to lamellar line, three pairs of notogastral porose areas, and notogastral porose area Aa elongate oval, A1 boomerang-form or banana-shaped, and by the absence of dorsosejugal suture and median pore. An identification key and data on distribution and ecology of known species of Angulogalumna are presented.http://www.zoobank.org/urn:lsid:zoobank.org:pub:E6193F26-F6AE-4759-9CA3-F6780D75452D

<p class="Body"><strong>Con</strong><strong>tribution to the knowledge of African Parakalummidae<em> </em>(Acari, Oribatida)</strong></p>

Two new species of oribatid mites of the genus Neoribates (Oribatida, Parakalummidae) are described based on adult specimens from leaf litter in the Montagne d'Ambre National Park of North Madagascar. Neoribates africanus sp. nov. and N. madagascarensis sp. nov. clearly differs from all species of the genus by the absence of interlamellar seta (including alveolus). An identification key and data on distribution and ecology of known African species of Parakalummidae are presented.

New and interesting species of the genera Galumna and Pergalumna (Acari, Oribatida, Galumnidae) from the Montagne d'Ambre National Park, Madagascar

This work includes taxonomic and faunistic data on galumnid mites (Oribatida, Galumnidae) belonging to the genera Galumna and Pergalumna collected from the Montagne d'Ambre National Park, North Madagascar. Two new species are described: Galumna sandormahunkai n. sp. differs from its closest species, Galumna sphagni by the larger body size, the presence of strongly protruding rostrum, lanceolate, pointed apically bothridial setae, the direction of lamellar lines, and the absence of median pore; Pergalumna janosbaloghi n. sp. differs from the most similar species, Pergalumna aegra, by the smaller body size and the presence of long lamellar setae and elongate, distinctly or slightly triangular porose areas Aa. Galumna granalata and Pergalumna amamiensis are recorded in the Ethiopian region for the first time; Pergalumna conspicua and P. frater are recorded in Madagascar for the first time.

Polymorphism and synonymy of Brookesia antakarana and B. ambreensis, leaf chameleons from Montagne d'Ambre in north Madagascar

Polymorphism and synonymy of Brookesia antakarana and B. ambreensis, leaf chameleons from Montagne d'Ambre in north Madagascar

Splitting and lumping: An integrative taxonomic assessment of Malagasy chameleons in the Calumma guibei complex results in the new species C. gehringi sp. nov.

Calumma guibei (Hillenius, 1959) is a high-altitude chameleon species from the Tsaratanana massif in north Madagascar. Since its description was based on a juvenile holotype, its taxonomic identity is uncertain and little is known about its morphology. A recent molecular study discovered several deep mitochondrial clades in the Tsaratanana region assigned to C. guibei and C. linotum (Müller, 1924). In this paper we study the taxonomy of these clades and clarify the identity of C. guibei. Using an integrative taxonomic approach including pholidosis, morphological measurements, osteology, and molecular genetics we redescribe C. guibei and describe the new species C. gehringi sp. nov. which comprises two deep mitochondrial lineages. In terms of external morphology the new species differs from C. guibei by an elevated rostral crest, the shape of the notch between the occipital lobes (slightly connected vs. completely separated), presence of a dorsal and caudal crest in males (vs. absence), and a longer rostral appendage in the females. Additionally, we analysed skull and hemipenis morphology using micro-X-ray computed tomography (micro-CT) scans and discovered further differences in skull osteology, including a large frontoparietal fenestra, and separated prefrontal fontanelle and naris in C. guibei. Furthermore, we provide a comparison of micro-CT scans with traditional radiographs of the skull. The hemipenes have ornaments of two pairs of long pointed cornucula gemina (new term), two pairs of dentulous rotulae, and a pair of three-lobed rotulae, and are similar in both species, but significantly different from other species in the C. nasutum group. Geographically, C. guibei has been recorded reliably from the higher elevations of the Tsaratanana Massif above 1580 m a.s.l., whereas C. gehringi sp. nov. is found at mid-altitude (730–1540 m a.s.l.) in Tsaratanana and the surrounding area.

A new species of Diastatotropis Lacordaire (Coleoptera: Anthribidae) from Montagne d'Ambre National Park, northern Madagascar.

A new species, Diastatotropis perrinae Trýzna & Baňař sp. nov. (Anthribidae: Anthribinae: Cappadocini), from north Madagascar is described. Male genitalia are studied and illustrated and colour photographs are added. A comparison with the most similar known species, D. tigrinus Lacordaire, 1866, is provided.

Prevalence of Rheumatic Heart Disease in North Madagascar: An echocardiographic screening in young and adult populations

Prevalence of Rheumatic Heart Disease in North Madagascar: An echocardiographic screening in young and adult populations

Gecko phylogeography in the Western Indian Ocean region: the oldest clade of Ebenavia inunguis lives on the youngest island

AbstractAimWe studied the gecko genus Ebenavia to reconstruct its colonization history, test for anthropogenic versus natural dispersal out of Madagascar, and correlate divergence date estimates of our phylogeny with geological age estimates of islands in the region.LocationMadagascar and surrounding islands of the Western Indian Ocean (Comoros, Mayotte, Mauritius, Pemba).MethodsWe reconstructed the phylogeny of Ebenavia covering its entire geographical range using a molecular data set of three mitochondrial and two nuclear markers. We estimated divergence times based on calibrations using (1) previously calculated mutation rates of mitochondrial markers, (2) a combination of these rates with old or (3) young geological age estimates for some of the islands inhabited by the genus, and (4) an independent data set with fossil outgroup calibration points.ResultsEbenavia inunguis, one of two recognized species of the genus, comprises multiple ancient evolutionary lineages. The earliest divergence within this complex (Miocene, 13–20 Ma; 95% credibility interval [CI]: 4–29 Ma) separates the population of the Comoros Islands, excluding Mayotte, from all other lineages. The age estimates for island lineages coincide with the geological age estimates of the islands except for Grand Comoro, where the age of the local clade (3–5 Ma; 95% CI: 2–7 Ma) significantly predates the estimated island age (0·5 Ma). A clade from north Madagascar + Mayotte + Pemba is estimated to have diverged from an eastern Malagasy clade in the Miocene.Main ConclusionsOur results suggest that Grand Comoro Island is geologically older than previously estimated. The islands of the Comoros and Pemba were probably colonized via natural dispersal out of Madagascar (> 1000 km in the case of Pemba). Mauritius was most likely colonized only recently from eastern Madagascar via human translocation.

First observational evidence of a North Madagascar Undercurrent

In situ observations reveal a southeastward-directed North Madagascar Undercurrent (NMUC) below and opposite to the equatorward-directed North Madagascar Current (NMC) off Cape Amber, at the northern tip of Madagascar. Results show an undercurrent hugging the continental slope with its core at 460m depth and velocities over 0.7ms−1. Its volume transport is estimated to be 3.1–3.8Sv, depending on the velocity extrapolation methods used to fill in the data gaps near the slope (no-slip and full-slip, respectively). The thermohaline characteristics show a saltier and warmer NMUC, compared to the surrounding offshore waters, transporting mainly South Indian Central Water. Also, strong horizontal gradients of density are found in the NMUC domain. An inshore cell of coastal downwelling due to Ekman Transport toward the coast is identified, which can explain, at least in part, the strong baroclinic pressure gradients as well as the NMUC development and possible persistence.

Leaping towards a saltatorial lifestyle? An unusually long-legged new species of Rhombophryne (Anura, Microhylidae) from the Sorata massif in northern Madagascar

The Madagascar-endemic microhylid genus Rhombophryne consists of a range of partly or completely fossorial frog species. They lead a poorly known, secretive lifestyle, and may be more diverse than previously thought. We describe a new species from the high altitude forests of the Sorata massif in north Madagascar with unusual characteristics for this genus; R. longicrus sp. n. has long, slender legs, unlike most of its fossorial or semi-fossorial congeners. The new species is closely related to R. minuta, a much smaller frog from the Marojejy massif to the southeast of Sorata with similarly long legs. We discuss the morphology of these species relative to the rest of the genus, and argue that it suggests adaptation away from burrowing and toward a more saltatorial locomotion and an accordingly more terrestrial lifestyle. If this is the case, then these frogs represent yet more ecological diversity within the already diverse Cophylinae. We recommend an IUCN Red List status of Endangered B1ab(iii) for R. longicrus sp. n., because it is known only from a single site in a forested area of roughly 250 km2, which is not yet incorporated into any protected area.

A new species of Tophoderes Dejean from northern Madagascar with a checklist of the species (Coleoptera: Anthribidae)

A new species, Tophoderes lidmilae Trýzna & Baňař sp. nov., from north Madagascar is described. Male genitalia are studied and illustrated and colour photographs of both sexes are added. A comparison with the most similar known species T. frenatus (Klug, 1833) is provided. A checklist of species of the Madagascan genus Tophoderes (Anthribidae: Anthribinae: Tophoderini) is provided.

Rare seabird sightings off north and west Madagascar, January–February 2014

Rare seabird sightings off north and west Madagascar, January–February 2014